Screening and differential oxidative stress responses of hot pepper (Capsicum annuum L.) genotypes under cold stress

Abstract

Cold stress (CS) anomalies have recently increased, major abiotic threat that delimit chilli production and yield. Cold tolerance is differing between genotypes, especially in commercial crops like hot pepper (chilli). specific investigations are required to understand biochemical and physiological changes in response to Cold stress (CS). Crop selection for increased tolerance needs traits with high sensitivity, fast and cost effective. This study aimed to select chilli genotypes which revealing differential tolerance to CS at seedling stage. Accordingly, 12 chilli genotypes were examined under two cold regimes including control (35/25 °C – day/night) and CS (10/8 °C – day/night). Multivariate cluster analysis of 14 traits grouped the genotypes into three clusters under stress condition, indicating that CS influencing physiology and oxidative potential of chilli seedlings. Chlorophyll, Membrane stability, Hydrogen peroxide content, lipid peroxidation and proline, phenolic contents are the influential traits for evaluating the impact of cold stress. ROS and ROS mediated traits showed a differential performance among the genotypes tested. Enzymatic antioxidants were significantly increased across all genotypes. Decrements of pungency levels in chilli fruits were significant only in CA-173 and F-02 genotypes. Altogether, the antioxidant profile has explored there is an association between capsaicinoid levels and antioxidant activities, antioxidants may involve preserving capsaicinoid metabolism to maintain the quality of chilli fruits during CS. Grouping of genotypes by cluster analysis is correlated with cold injury index and chlorophyll stability index under CS conditions. These indices can be employed as proper screening indices for cold tolerance in chilli genotypes. . • Simulated short-term cold stress has differential negative impacts among Chilli genotypes. • Differential levels of ROS generation and antioxidant potential among the genotypes tested. • ROS-induced oxidation of capsaicinoids was countered by antioxidant enzymes and chilli fruit quality was maintained under short-term cold stress. • 12 genotypes were grouped into 3 clusters: 1 – Sensitive; 2 – Moderately tolerant; 3 – Tolerant. • Cold injury index and Chlorophyll stability index can be used as cost-effective screening indices for selection of cold-tolerant chilli genotypes.